It is known that a non-acidic zeolite catalyst, such as Pt/K-Ba L-Zeolite or Pt/K L-Zeolite, can be used to reform a wide boiling range naphtha (C.sub.6 -C.sub.10). The resulting product would be aromatics, namely benzene, toluene, and C.sub.8 and C.sub.9 aromatics. The C.sub.8 aromatics fraction would normally have a product distribution which contains 30-35% ethylbenzene and 65-70% xylenes. In addition, the xylenes distribution would normally show a para-xylene content well below equilibrium, namely 10-14%.
In contrast, when reforming the same naphtha with a standard reforming bi-metallic catalyst with an acidic function, such as Pt-Re or Pt-Sn on alumina, the C.sub.8 aromatics fraction has a product distribution which contains about 15% ethylbenzene and 85% xylenes. As for the xylenes distribution, the para-xylene content is closer to equilibrium, i.e. about 20%. However, in terms of aromatics production, the standard reforming catalyst is much less selective than the non-acidic zeolite, and the overall aromatics yield is much lower.
Thus, while there is an advantage in reforming with a non-acidic zeolite, the high ethylbenzene content of the C.sub.8 aromatics fraction and the below equilibrium para-xylene concentration in the xylenes fraction present a distinct disadvantage to a para-xylene producer. This disadvantage means that a bigger para-xylene processing loop is required to handle the higher ethylbenzene content and below para-xylene equilibrium C.sub.8 aromatics fraction, which in turn means a processing scheme with higher capital investment and operating costs. In addition,more xylenes will be lost per pass, resulting in a lower para-xylene yield from a given quantity of xylenes. This adds to the higher operating costs.